Process for low pressure synthesis of ethylene glycol from synthesis gas plus 1,3-dioxolane

ABSTRACT

This invention relates to the manufacture of ethylene glycol and more particularly to a low pressure process for making ethylene glycol comprising reacting synthesis gas, i.e. a mixture of carbon monoxide and hydrogen, plus 1,3-dioxolane in the presence of a homogenous liquid catalyst containing an effective amount of cobalt-containing compound and a silane or germane-containing promoter dispersed in a hydrocarbon solvent at a temperature of at least 50° C. and a pressure of at least 500 psi, where the particular solvents used allow the desired product to be separated from the reaction mixture by phase separation.

This application is related to copending U.S. patent application Ser.Nos. 663,281, 663,284 and 663,602, filed of even date.

FIELD OF THE INVENTION

This invention relates to a new process for preparing ethylene glycol.More particularly, this invention relates to a novel process forpreparing ethylene glycol in high yields from syngas which comprisescontacting syngas, (a mixture of carbon monoxide and hydrogen), plus1,3-dioxolane with a catalyst comprising a cobalt-containing compoundand a silane or germane promoter dispersed in a hydrocarbon solvent at atemperature of at least 50° C. and a moderate pressure of at least 500psig.

BACKGROUND OF THE INVENTION

Ethylene glycol is a chemical which has found wide use in industry. Itis used, for example in the preparation of plasticizers for vinylpolymers and as a component in polyester fibers and antifreezeformulations. In view of its many uses, there is a need to find new andmore economical methods for preparing ethylene glycol.

Proposed methods for making ethylene glycol involve the reaction ofcarbon monoxide with hydrogen in the presence of various proposedcatalyst systems at elevated temperatures and pressures. For example,one of the earliest disclosed processes for making polyhydroxy compoundsfrom readily available and inexpensive starting materials such asformaldehyde, carbon monoxide and hydrogen was disclosed in U.S. Pat.No. 2,451,333. The process comprised heating the starting materials witha reduced cobalt oxide hydrogenation catalyst under a high pressure, inexcess of 100 atm. and at a temperature from about 80° C. to 300° C.Actually the examples in this patent used high pressures in the range of500-800 atmospheres.

In Japan Kokai No. 76,128,903 (1976) to Mitsubishi a procedure isdisclosed for preparing ethylene glycol by the reaction of CO, H₂ andHCHO with a cobalt catalyst containing a trivalent P, As or Sb compoundat a temperature of about 160° C. and a pressure of about 180 Kg/cm², orapproximately 2700 psi.

Similarly U.S. Pat. No. 4,144,401 uses CO, H₂ and formaldehyde asstarting materials, but they are reacted in the presence of an alcoholsolvent and a catalytic amount of rhodium or a rhodium-containingcompound at a moderate temperature and pressure. Of course use ofrhodium in a catalyst makes it expensive for commercial purposes.Methanol is also produced in substantial amounts in this process.

U.S. Pat. No. 4,356,332 pertains to the production of ethylene glycol byreaction of formaldehyde with carbon monoxide and hydrogen in thepresence of a catalyst comprising a cobalt-containing compound and atin-or germanium-containing promoter and in the presence of asubstantially inert, oxygenated hydrocarbon solvent.

In U.S. Pat. No. 4,200,765 there is disclosed a process for preparingglycol aldehyde by reacting formaldehyde, hydrogen and carbon monoxidein an aprotic solvent at elevated temperatures and superatmosphericpressures in the presence of a rhodium catalyst with subsequentconversion of the glycol aldehyde to ethylene glycol by hydrogenation.

Japan Kokai No. 82,118,527 (1981) to Mitsubishi discloses the use of aruthenium-based catalyst with a trivalent phosphorous compound toconvert formaldehyde, CO and H₂ into ethylene glycol. The selectivity toethylene glycol is not specified.

Japan Kokai No. 82,130,940 (1981) to Mitsui Petrochemicals employs arhodium compound and an alkali metal compound. Again selectivity toethylene glycol is not specified.

In U.S. Pat. No. 4,367,820 only carbon monoxide and hydrogen, withoutformaldehyde are used as starting materials for conversion to ethyleneglycol via a catalyst comprising a cobalt-containing compound and alarge excess of organosilicon compound. In most of the examples anoperating temperature range of 250°-270° C. is employed, coupled withpressures of about 4000-8000 psi. Weight ratios of ethylene glycol tomethanol were typically Ca. 2:1.

Additional Japanese applications disclose the use of a solution offormalin, carbon monoxide and hydrogen to produce ethylene glycol in thepresence of a cobalt catalyst. See Japanese Application No. 197909 toAgency of Ind. Sci. Tech. In Jap. Application No. 188137 to the sameagency, ethylene glycol is produced by reacting CO and hydrogenoptionally with formaldehyde in the presence of a cobalt carbonyl and aphenol and/or alkylphenol.

Japanese Application No. 004782 (1981) to Mitsubishi discloses a processfor producing ethylene glycol from formaldehyde, CO and H₂ in thepresence of a catalyst containing ruthenium and a trivalentorgano-phosphorous compound.

Finally in Japan Kokai Tokyo Koho JP No. 57,130,933 to Mitsubishi,acetals are reacted with CO and H₂ in the presence of a cobalt-iodinecatalyst system to produce ethylene glycol.

Many of these processes require the use of high pressures (particularlyin the absence of an added formaldehyde source), some use expensiverhodium-containing compounds and in most the selectivities for ethyleneglycol are not very substantial and separation of the desired product isdifficult.

The disclosure of a process for producing ethylene glycol from simplestarting materials such as syngas (i.e. carbon monoxide and hydrogen)and 1,3-dioxolane by reacting the starting materials in the presence ofa catalyst compound which would be relatively inexpensive, even on acommercial sale, and which could be reacted at low temperatures andpressures therefore allowing for less expense in construction ofreactors, etc. would be an advance in the art, especially if theselectivity for ethylene glycol were better than found in previous work.Further, it would be a considerable advance in the art if the desiredproduct could be obtained from the reaction mixture by a simple phaseseparation technique.

SUMMARY OF THE INVENTION

This invention concerns a process for making ethylene glycol comprisingcontacting a mixture of synthesis gas, i.e., carbon monoxide andhydrogen, plus 1,3-dioxolane with a catalyst comprising acobalt-containing compound and a silane or germane-containing compoundand heating the resultant mixture at a temperature of at least 50° C.and a pressure of at least 500 psi and preferably less than 5000 psi forsufficient time to produce the desired ethylene glycol. By using thiscatalyst system one can obtain high yields of ethylene glycol, theprocess can be operated at lower temperatures and pressures and the useof extreme conditions and expensive catalyst compounds required in manyof the prior known processes can be avoided. Also, the process providesfor ease of separation of the glycol products from the selected solvent.This results because, for example, where 1,2,4-trichlorobenzene is usedas a solvent, the glycol products separate as an aqueous rich phase.

The process of the invention, as far as the formation of the desiredethylene glycol is concerned, may be represented by the followingequation: ##STR1##

Typical concentrations of ethylene glycol in the crude liquid productrange up to 60 wt % of the phase which separates, typical yields ofethylene glycol (basis 1,3-dioxolane charged) range up to 50 mole %.Total glycol products may comprise up to greater than 65 wt % of thecrude liquid product phase.

A further advantage of this process is that there appears to be nocompeting water-gas shift or methanation activity with this class ofsolvent solubilized cobalt-silane or cobalt-germane catalyst. Ethyleneglycol/methanol ratios in the crude liquid product may exceed 25:1.

DETAILED DESCRIPTION OF THE INVENTION

In the operation of the process of the invention, ethylene glycol isprepared from a synthesis gas mixture of carbon monoxide and hydrogenplus 1,3-dioxolane by a process comprising the following steps:

(a) contacting said mixture of carbon monoxide, hydrogen and1,3-dioxolane with a catalyst comprising a cobalt-containing compoundand a silane or germane-containing compound dispersed in a solventselected from the group including halogen-containing aromatic andhydrocarbyl ether solvents, said solvent allowing separation of glycolproducts from the main body of the solvent,

(b) heating said mixture to a temperature of at least 50° C. under apressure greater than 500 psi with sufficient carbon monoxide andhydrogen to satisfy the above-noted stoichiometry of the desiredethylene glycol synthesis until substantial formation of the desiredethylene glycol has been achieved; and

(c) preferably isolating said ethylene glycol by separation of anaqueous-rich phase from the main body of the selected solvent.

In order to present the inventive concept of the present invention inthe greatest possible detail, the following supplementary disclosure issubmitted. The process of the invention is practiced as follows:

As noted, the new catalyst system used in the process of the inventioncontains a cobalt-containing compound and a silane or germane-containingpromoter. The cobalt compound to be used may be chosen from a widevariety of organic and inorganic compounds, complexes, etc. It is onlynecessary that the catalyst employed contain the cobalt in any of itsionic states.

The cobalt-containing compound employed may take many different forms.For instance the cobalt may be added to the reaction mixture in an oxideform as in the case of, for example, cobalt(II) oxide, (CoO) orcobalt(II,III) oxide (Co₃ O₄). Alternatively, it may be added as thesalt of a mineral acid, as in case of cobalt(II) nitrate hydrate(Co(NO₃)₂.6H₂ O), cobalt(II) phosphate, cobalt(II) sulfate, etc. or asthe salt of a suitable organic carboxylic acid, for example, cobalt(II)formate, cobalt(II) acetate, cobalt(II) propionate, cobalt naphthenate,or bonded to a carbonyl-containing ligand as in the case of cobaltacetylacetonate, etc. The cobalt may also be added to the reaction zoneas a carbonyl or hydridocarbonyl derivative. Here, suitable examplesinclude dicobalt octacarbonyl, (Co₂ (CO)₈), cobalt hydridocarbonyl,(HCo(CO)₄) and substituted carbonyl species such as the organophosphoruscobalt carbonyls like HCo(CO)₃ (Bu₃ P).

Preferred cobalt-containing compounds include oxides of cobalt, cobaltsalts of mineral acids, cobalt salts of organic carboxylic acids andcobalt carbonyl or hydridocarbonyl derivatives. Among these,particularly preferred are dicobalt octacarbonyl, cobalt(II) oxide,cobalt(II) nitrate, cobalt acetylacetonate and cobalt(II) acetate.

The silane or germane-containing promoter employed in the practice ofthis invention may also take many different forms. Generally, thesilicon-containing promoter should contain at least one bond between asilicon atom and a carbon atom, but suitable organosilicon compounds maycomprise mono-, di-, tri- and tetraorgano groups bonded to silicon. Eachorgano group may be an alkyl, aryl or aryalkyl moiety, having one to 20carbon atoms. The silicon-containing promoter may also containsilicon-oxygen bonds, and preferred promoters are halogen-free silanescontaining at least one silicon-hydrogen bond per molecule.

Typical organosilicon compounds that are suitable for use in the processof equation (1) include trialkylsilanes, such as triethylsilane (Et₃SiH), tricyclohexylsilane [(C₆ H₁₁)₃ SiH], trimethylsilane,tri-n-hexylsilane and methyldiethylsilane (MeEt₂ SiH), as well asdimethylethylsilane and the tripropylsilanes, the dialkylsilanes such asdiethylsilane (Et₂ SiH₂) and dimethylsilane, the tetraalkylsilanes suchas tetramethylsilane and tetraethylsilane, the arylsilanes such astriphenylsilane (Ph₃ SiH), diphenylsilane and hydroxytriphenylsilane, aswell as the alkoxysilanes such as triethoxysilane [(EtO)₃ SiH],phenyltriethoxysilane, tetraethoxysilane and tetramethoxysilane. Lesssatisfactory are the halogenated organosilanes such aschlorotrimethylsilane, dimethylsilane chloride (Me₂ SiHCl),chlorotriphenylsilane, dichlorodimethylsilane (Me₂ SiCl₂),chlorotriethylsilane, and iodotrimethylsilane. Other suitableorganosilicon promoters containing at least one silicon-hydride bond,and more than one silicon atom per molecule, include:

H₃ SiCH₂ SiH₃

H₃ SiCH₂ CH₂ SiH₃

CH₃ SiH₂ CH₂ SiH₃ ##STR2##

Suitable silanes containing more than one silicon-hydride bond permolecule are exemplied by:

C₆ H₁₃ SiH₃

CH₃ CH═CHCH₂ SiH₃ ##STR3## CH₂ ═CHCH₂ SiH₃ C₆ H₅ CH₂ CH₂ SiH₃

C₆ H₅ CH(CH₃)SiH₃

(C₃ H₇)₂ SiH₂

(CH₃)(isoC₄ H₉)SiH₂

(C₂ H₅)(isoC₄ H₉)SiH₂

(CH₂ ═CH)(C₂ H₅)SiH₂

(CH₂ ═CH)(C₄ H₉)SiH₂

Also effective as silicon-containing promoters in the practice of thisprocess are siloxanes and polyalkylsiloxanes. These may includehexaethyldisiloxane, hexamethylcyclotrisiloxane,octamethylcyclotetrasiloxane, hexamethyldisiloxane,tetramethyldisiloxane (Me₂ HSiOSiHMe₂), methylhydrocyclosiloxane, or thealkylsiloxane polymers of the type: ##STR4## wherein R is one ordifferent alkyl groups containing 1 to 6 carbon atoms.

Equally useful are the higher M.W. tetraalkylsilanes andtetraalkoxysilanes wherein each alkyl or alkoxy group contains 1 to 20carbon atoms, and each alkyl group may have the same or different carbonnumber.

Preferred organosilane compounds include triethylsilane,triphenylsilane, trimethylsilane, diphenylsilane, tricyclohexylsilane,tetramethylsilane, tetraethylsilane, hydroxytriphenylsilane,diethylsilane and tripropylsilane.

The germanium-containing compound which may be utilized with thecobalt-containing compounds in this process may also take many differentforms. For instance, the germanium may be added to the reaction mixturein the form of a halide, such as germanium tetrachloride, germaniumdiiodide and germanium tetrabromide, or as a hydrocarbylgermaniumcompound such as tetra-n-butylgermane, tetraethylgermane,tetraphenylgermane and tetramethylgermane, or an organohalide germaniumcompound such as diphenylgermanium chloride, methylgermaniumtrichloride, phenylgermanium trichloride, tri-n-butylgermanium iodide,triethylgermanium chloride, triethylgermanium iodide, trimethylgermaniumchloride, triphenylgermanium bromide and triphenylgermanium chloride, oras an organogermanium hydride, such as triphenylgermanium hydride, or asan organogermanium oxide or carboxylate such as triphenylgermaniumacetate, or as a germanium alkoxide such as germanium butoxide,germanium ethoxide or germanium methoxide.

The preferred germanium-containing promoter compounds are theorgano-halide germanium compounds, the hydrocarbyl germanium compounds,and the organogermanium hydrides. Among these, particularly preferredare triphenylgermanium bromide, trimethylgermanium bromide,triphenylgermanium hydride, tetraphenylgermane, tetraethylgermane andtriethylgermanium chloride.

As characterized above, this process is operated as a homogeneous liquidphase mixture. The process is typically carried out in a solvent. Thesolvent should preferably be a liquid at room temperature but should atleast, in part, be a liquid under the conditions of reaction. Thesolvent is selected such that it is capable of:

(a) Maintaining the cobalt catalyst in the homogeneous liquid phasemixture throughout the synthesis of desired ethylene glycol.

(b) Ensuring good selectivity and yields to desired ethylene glycol andits derivatives.

(c) Achieving separation of the majority of the ethylene glycol productas a separate liquid phase from the cobalt catalyst-rich solvent phaseat the completion of the desired glycol synthesis.

Three classes of hydrocarbon solvent are discussed herein that areuseful in the process of this invention and which satisfy the criteriadescribed supra; those include halogenated aromatic-containing solvents,hydrocarbyl ether solvents, and aromatic hydrocarbon solvents.

Generally these solvents will contain up to 20 carbon atoms per moleculeand preferable a maximum of 4 halogen atoms per molecule. The solventmust be substantially inert under typical Co-hydrogenation conditionsthat yield glycol products and it must be one which has a normal boilingpoint of at least 65° C. at atmospheric pressure. Preferably, thesolvent will have a boiling point greater than that of methanol andother oxygen-containing reaction products so that recovery of the glycolproduct by distillation is facilitated.

Suitable halogen-containing solvents that are satisfactory for thisglycol process contain up to 20 carbon atoms per molecule and preferablyno more than 4 halogen atoms per molecule. They are exemplified by, butnot limited to, chlorobenzene, bromobenzene, o-dichlorobenzene,1,2,4-trichlorobenzene, 1,3,5-tribromobenzene, p-bromotoluene,2-bromo-m-xylene, α-bromo-p-xylene, 2-chlorobiphenyl, 7-chlorobiphenyl,o-dibromobenzene, 2,2'-dibromobiphenyl, 4,4'-dibromobiphenyl,2,5-dibromotoluene, 2,4,6-tribromotoluene, 2,3,6-trichlorotoluene,p-xylene dichloride and 1,2,4-trifluorobenzene.

Also effective are aromatic and aliphatic solvents containing the etherlinkage. Examples of such solvents include anisole, p-dioxane, ethyleneglycol dimethyl ether, tetrahydrofuran, triethyleneglycol dimethylether, diphenyl oxide, as well as halogenated ether solvents such asp-bromoanisole, m-chloroanisole, and brominated diphenyl oxide.

Suitable aromatic-type solvents that are satisfactory in the practice ofthis invention contain 6 to 20 carbon atoms per molecule and at leastone aromatic ring moiety per molecule. They are exemplified by, but notlimited to, benzene, toluene, p-xylene, o-xylene, m-xylene, mixedxylenes, ethylbenzene, mesitylene, biphenyl, cumene, diethylbenzene,diphenylmethane, dixylyethane, durene, ethyl toluenes, fluorene,naphthalene, n-nonylbenzene, phenyltoluenes, stilbene, tetralin,tetramethylbenzenes, tetraphenylmethane, and n-propylbenzene.

The most effective solvents in terms of (a) glycol concentration in thecrude aqueous phase of the liquid product, (b) total glycol productyield and (c) cobalt recovery in solution appear to be halogenatedsolvents of the group including o-dichlorobenzene,1,2,4-trichlorobenzene, p-bromoanisole, m-chloroanisole, bromobenzeneand dibromobenzene. There appears to be very little competing water-gasshift or methanation activity with this class of solvent-solubilizedcobalt-silane or cobalt-germane catalyst. Ethylene glycol/methanolratios may reach 25:1 or better.

The quantity of cobalt-containing compound and the silane orgermane-containing compound to be used in the process of the inventionmay vary. The process is conducted in the presence of a catalyticallyeffective quantity of the active cobalt-containing compound and theactive silane or germane-containing compound which gives the desiredproduct in a reasonable yield. The reaction proceeds when employing aslittle as about 10⁻² weight percent, and even lesser amounts of thecobalt-containing compound, together with as little as about 10⁻² weightpercent of the silane or germane-containing compound based on the totalweight of the reaction mixture. The upper concentration is dictated by avariety of factors including catalyst cost, partial pressures of carbonmonoxide and hydrogen, operating temperature, etc. A cobalt-containingcompound concentration of from about 10⁻² to about 30 weight percent inconjunction with a silane or germane-containing compound concentrationof from about 10⁻² to about 50 percent and a solvent concentration ofabout 10 to 95 percent, based on the total weight of the reactionmixture is generally desirable in the practice of this invention.

Particularly superior results are obtained when the above-notedcomponents of the catalyst system are combined as follows on a molarbasis: cobalt-containing compounds to silane or germane-containingcompound of 1:0.1 to 1:100.

The temperature range which can be employed in the process of theinvention may vary over a considerable range depending upon experimentalfactors, including the choice of catalyst, pressure and other variables.A preferred range of operability is from about 50° C. to about 350° C.when superatmospheric pressures of syngas are employed. A narrower rangeof about 100° C. to 220° C. represents a preferred temperature range.

The pressure employed may also vary over a considerable range, but inmost cases is at least above 500 psig. A preferred operating rangevaries from about 1000 psig to about 6000 psig, although pressures above6000 psig also provide useful yields of the desired product. Thepressures referred to herein represent the total pressure generated byall the reactants, although they are substantially due to the carbonmonoxide and hydrogen fractions. In the presence of 1,3-dioxolane, thetotal pressures required for glycol syntheses using cobalt/silane orgermane-promoted catalyst systems are normally lower than thosepressures required for direct glycol production from CO/H₂ (See, forexample, U.S. Pat. No. 4,367,820).

The relative amounts of carbon monoxide and hydrogen which can beinitially present in the syngas mixture are variable, and these amountsmay be varied over a wide range. In general, the mole ratio of CO:H₂ isin the range from about 20:1 to about 1:20, and preferably from about5:1 to 1:5, although ratios outside these ranges may also be employedwith good results. Particularly in continuous operations, but also inbatch experiments, the carbon monoxide-hydrogen gaseous mixture may alsobe used in conjunction with up to 50% by volume of one or more othergases. These other gases may include one or more inert gases such asnitrogen, argon, neon, and the like, or they may include gases that may,or may not, undergo reaction under carbon monoxide hydrogenationconditions, such as carbon dioxide, hydrocarbons, such as methane,ethane, propane, and the like, ethers, such as dimethyl ether,methylethyl ether and diethyl ether and alkanols, such as methanol.

In all these synthesis in order to achieve a high degree of selectivitythe amount of carbon monoxide, hydrogen and 1,3-dioxolane present in thereaction mixture should be sufficient to at least satisfy thestoichiometry of the desired formation of ethylene glycol as shown inequation (1) above. Excess carbon monoxide and/or hydrogen over thestoichiometric amount may be present, if desired.

The most desired product of this synthesis, ethylene glycol (EG) will beformed in significant quantities (up to Ca. 60 wt % concentration in thecrude liquid product) and up to Ca. 50 mole % yield (basis total1,3-dioxolane charged) using the cobalt-silane or germane promotedcatalyst system of this invention. Also formed are significant amountsof diethylene glycol (DEG), propylene glycol (PG), together withderivatives such as the ethylene glycol monoalkyl ethers (e.g. ethyleneglycol monomethyl ether, EGMME). Selectivity to total glycol products(EG+DEG+PG+EGMME) may exceed 65 wt %. Lower monohydric alcohols such asmethanol and ethanol are also present in the crude liquid product mix.Each of these oxygenated products including ethylene glycol, monohydricalcohols and other by-products can be recovered from the reactionmixture by conventional means, e.g. fractional distillation in vacuo.However, when halogenated aromatics and hydrocarbyl ethers are used asthe solvent, the products can be separated by a simple phase separationtechnique.

The novel process of the invention can be conducted in a batch,semi-continuous or continuous manner. The catalyst can be initiallyintroduced into the reaction zone batchwise, or it may be continuouslyor intermittently introduced into such a zone during the course of thesynthesis reaction. Operating conditions can be adjusted to optimize theformation of the desired ethylene glycol product, and said material maybe recovered by methods known to the art, such as distillation,fractionation, extraction and the like. A fraction rich in the catalystcomponents may then be recycled to the reaction zone, if desired, andadditional product generated.

The products have been identified in this work by one or more of thefollowing analytical procedures: viz, gas-liquid phase chromatography(glc), gas chromatography/infrared spectroscopy (GC/IR), nuclearmagnetic resonance (nmr) and elemental analyses, or a combination ofthese techniques. Analyses have, for the most part, been by parts byweight; all temperatures are in degrees centigrade and all pressures inpounds per square inch gauge (psig).

The yield of ethylene glycol in each synthesis (mole %) is estimatedbasis equation 1 using the formula: ##EQU1## Total liquid productincrease (wt %) is estimated basis:

To illustrate the process of the invention, the following examples aregiven. It will be apparent from the examples that ethylene glycolsynthesis in good yields has been demonstrated over a broad range ofoperating temperatures. It is to be understood, however, that theexamples are given in the way of illustration and are not to be regardedas limiting the invention in any way.

EXAMPLE I

A 450 ml capacity reactor with glass liner was charged with a mixture ofdicobalt octacarbonyl (12.0 mmole Co, 2.052 g), triethylsilane (24.0mmole Si, 2.790 g) and 1,3-dioxolane (200 mmole, 14.82 g), water (200mmole, 3.60 g) and 1,2,4-trichlorobenzene (15.0 g). The mixture wasflushed with nitrogen, the reactor sealed, flushed with synthesis gas,pressured to 2700 psig with CO/H₂ (1:2), and heated to 160° C. withagitation. After four hours, the reactor was allowed to cool, the gaspressure (2300 psig) noted, and the excess gas sampled and vented. 41.9g of two-phase liquid product was recovered, there was no solidprecipitate at this stage.

Analysis (glc) of the less dense liquid phase (20 ml) shows it tocontain:

50.9 wt % ethylene glycol (EG)

3.4 wt % ethylene glycol monomethyl ether (EGMME)

0.7 wt % propylene glycol (PG)

3.2 wt % diethylene glycol (DEG)

1.8 wt % methanol

0.1 wt % ethanol

1.2 wt % 1,2,4-trichlorobenzene

20.4 wt % water.

Analysis (glc) of the heavier liquid phase (15 ml) shows it to contain:

91.4 wt % 1,2,4-trichlorobenzene

0.3 wt % ethylene glycol

0.2 wt % ethylene glycol monomethyl ether

8.1 wt % unidentified material.

Analysis of the gas sample shows it to contain:

64% hydrogen

24% carbon monoxide

<0.1% carbon dioxide

<0.1% methane.

Estimated yield of ethylene glycol is 174 mmole.

The estimated yield of ethylene glycol (basis 1,3-dioxolane charged) is44 mole %.

The estimated liquid yield increase is 9.4 wt %.

EXAMPLES II-XIII

Examples II-XIII were conducted in the same way as Example I. In everyexample dicobalt octacarbonyl was the cobalt-containing catalyst usedand 1,2,4-trichlorobenzene was employed as the solvent. The promoterused was triethylsilane, Et₃ SiH, and the results in terms of weightpercent of ethylene glycol, propylene glycol, diethylene glycol, glycolmonomethyl ether etc. in the crude liquid product are shown in Table I.

It may be seen from an inspection of Table I that:

(a) Ethylene glycol is the predominant product fraction in many of theseruns.

In Run VIII, for example, the aqueous-glycol phase of the productfraction comprises:

59.2 wt % ethylene glycol, and

69.1 wt % total EG+PG+DEG+EGMME.

Likewise, in Example III, the aqueous-glycol phase comprised:

61.8 wt % ethylene glycol and

65.5 wt % total EG+PG+DEG+EGMME.

(b) Glycol synthesis has been demonstrated over a broad range ofoperating temperatures, pressures and 1,3-dioxolane/cobalt molar ratios.

                                      TABLE I                                     __________________________________________________________________________    SYNTHESIS OF ETHYLENE GLYCOL FROM SYNGAS PLUS 1,3-DIOXOLANE.sup.a             1,3-                                                                          dioxolane Water                                                                              Temp                                                                              Pres.                                                                             ←Liquid Product Composition (Wt. %)→       Example                                                                            (mmole)                                                                            (mmole)                                                                            (°C.)                                                                      (psig)                                                                            H.sub.2 O                                                                          MeOH                                                                              EtOH                                                                              EGMME EG PG DEG Solvent                                                                            Dioxolane            __________________________________________________________________________                             17.3                                                                             4.2 0.1 5.7   50.9                                                                             0.3                                                                              1.7 5.3  0.6                  II   200  200  160 2000                                                                                0.2                                                                              0.2     0.4   -- 0.1                                                                              1.6 91   0.6                                           14.9                                                                             4.0     3.2   61.8                                                                             0.3                                                                              0.2 1.3  6.1                  III  200  200  160 1000                                                                                0.1                                                                              0.2     0.2   0.2   0.5 86   79                                            27.7                                                                             1.0 0.1 0.3   32.6      11.7 26.0                 IV   200  200  160  500                                                                                0.1                                                                              0.2           0.2   0.3 53.7 38.6                                          23.2                                                                             1.6     2.5   47.9                                                                             0.4                                                                              1.3 2.2  5.8                  V    200  200  140 2000                                                                                           0.2         0.2 89.8 6.0                                           26.0                                                                             0.4     0.8   30.0                                                                             0.6                                                                              0.6 2.4  20.9                 VI   200  200  120 2000                                                                                           0.1   0.1       70.5 19.4                                          32.3                                                                             0.1     0.2   17.6                                                                             0.2    1.5  37.0                 VII  200  200  100 2000                                                                                0.6                                                                              0.1     0.2      0.1                                                                              0.1 57.8 38.9                                          17.4                                                                             7.5 0.4 7.8   59.2                                                                             0.2                                                                              1.9 1.6  --                   VIII 200  200  180 2000                                                                                0.4                                                                              0.4     0.7   0.5   2.7 87.8 0.1                                           19.6                                                                             7.7     3.2   49.8                                                                             0.3                                                                              0.7 1.6  11.0                 IX   200  200  200 2000                                                                                0.2                                                                              1.0     0.5   0.6   0.8 66.8 16.8                                          19.8                                                                             1.7     2.1   55.4                                                                             0.7                                                                              2.0 3.2  0.2                  X    400  400  160 .sup. 2700.sup.b                                                                       0.1     0.2   0.2                                                                              0.2    89.4 0.2                                           21.0                                                                             3.3 0.9 5.6   48.8                                                                             0.4                                                                              4.6 1.1  0.3                  XI   200  200  180 5000                                                                                0.2                                                                              0.2 0.1 0.6   0.3   1.2 86.6 0.1                                           21.6                                                                             1.1 2.4 5.0   48.2                                                                             0.5                                                                              6.5 5.7  2.1                  XII  200  200  180 .sup. 5000.sup.c                                                                       0.2 0.5 0.8   0.1   2.8 83.7 0.8                                           20.0                                                                             1.7 1.0 4.6   49.9                                                                             0.8                                                                              7.0 2.0  0.7                  XIII 200  200  180 8000                                                                                   0.1 0.1 0.1   0.3                                                                              0.3                                                                              1.0 89.1 0.3                  __________________________________________________________________________     .sup.a Charge: Co, 12.0 mmole; Si, 24.0 mmole; Run Conditions CO/H.sub.2,     1:2; 4 hours; constant pressure                                               .sup.b Initial Pressure                                                       .sup.c Run for 18 hours                                                  

Table II shows the volume of the liquid product in Examples II throughXII. Also given is the ethylene glycol yield for each sample in mmoles.

                  TABLE II                                                        ______________________________________                                               Liquid Product   EG Yield                                              Example  Volume (ml)  Weight (g)                                                                              (mmole)                                       ______________________________________                                        II       18                                                                                             39.6    156                                                  15                                                                   III      16                                                                                             38.6    167                                                  16                                                                   IV       9                                                                                              36.1     47                                                  21                                                                   V        19                                                                                             39.7    151                                                  15                                                                   IV       16                                                                                             38.3     78                                                  17                                                                   VII      11                                                                                             38.1     40                                                  22                                                                   VIII     17                                                                                             38.8    166                                                  16                                                                   XI       14                                                                                             36.5    109                                                  18                                                                   X        38                                                                                             62.0    392                                                  12                                                                   XI       19                                                                                             41.4    149                                                  17                                                                   XII      21                                                                                             42.1    154                                                  18                                                                   XIII     20                                                                                             41.9    197                                                  18                                                                   ______________________________________                                    

EXAMPLES XIV-XIX

Examples XIV through XIX were conducted in the same manner as Example I.The catalyst used in each case was dicobalt octacarbonyl and thepromoter was triethylsilane. Different solvents were used and the effectupon ethylene glycol and total glycol production is shown in Table III,while Table IV illustrates the effect on liquid product volume/weightand gas composition.

It may be noted from an inspection of Tables III and IV that:

(a) Both chlorinated aromatic solvents, such as o-dichlorobenzene, andhydrocarbyl ether solvents, such as p-dioxane and anisole, are found tobe effective for the production of ethylene glycol in good selectivityand yields from syngas plus 1,3-dioxolane.

(b) There appears to be very little competing water-gas shift ormethanation activity with this class of solvent-solubilized,cobalt-silane catalyst.

(c) Ethylene glycol/methanol ratios in the crude liquid product phasemay exceed 25:1 in some cases (e.g. Example XVII).

                                      TABLE III                                   __________________________________________________________________________    ETHYLENE GLYCOL SYNTHESIS FROM SYNGAS PLUS 1,3-DIOXOLANE                                                  ←Liquid Product Composition (Wt                                          %)→                                                  1,3-                                             1,3-               Exam-     dioxolane                                                                          Water                                                                              Temp                                                                              Pres.                          Sol-                                                                              Dioxo-             ple Solvent                                                                             (mmole)                                                                            (mmole)                                                                            (°C.)                                                                      (psig)                                                                            H.sub.2 O                                                                        MeOH                                                                              EtOH                                                                              EGMME EG PG DEG vent                                                                              lane               __________________________________________________________________________    XIV p-dioxane                                                                           100  100  160 2700.sup.b                                                                        8.9                                                                              0.9 0.6 3.4   13.3                                                                             0.2                                                                              8.4 61.3                                                                              0.2                                            0.5                                                                              0.2 0.1 0.3   0.2   1.4 39.6                                                                              0.1                XV  "     200  200  160 2700.sup.b                                                                        10.6                                                                             0.8     0.6   30.7                                                                             0.2                                                                              4.1 48.0                                                                              --                                             0.4              0.3                                                                              0.4                                                                              0.3 22/72                                                                             --                 XVI Anisole                                                                             100  100  160 2700.sup.b                                                                        16.8                                                                             1.7 0.3 8.4   32.1                                                                             2.9                                                                              18.4                                                                              10.3                                                                              0.1                                            3.2                                                                              0.2     0.1   0.3                                                                              0.2                                                                              0.7 82.4                   XVII                                                                              Anisole                                                                             200  200  160 2700.sup.b                                                                        19.0                                                                             1.9 0.2 5.2   51.3                                                                             0.6                                                                              7.8  6.9                                                                              --                                             0.2                                                                              0.2     0.7   0.9   1.0 90  --                 XVIII                                                                             Anisole                                                                             200  200  160 2000.sup.d                                                                        15.7                                                                             3.6 0.2 7.3   50.0                                                                             0.2                                                                              6.2  7.9                                                                              0.2                                            0.3                                                                              0.4     1.2   0.9                                                                              0.2                                                                              0.7 90  0.2                XIX o-Dichloro-                                                                         100  100  160 2700.sup.b                                                                        14.5                                                                             2.6 0.3 7.5   45.0                                                                             0.6    18.5                                                                              0.1                    benzene                 0.1                                                                              0.3     0.9   0.7                                                                              0.2    93  --                 __________________________________________________________________________     .sup.a Charge: CO, 12.0 mmole, Si, 24.0 mmole; Run Conditions CO/H.sub.2,     1:2; 4 hours                                                                  .sup.b Initial Pressure                                                       .sup.c Not Determined                                                         .sup.d Constant Pressure                                                      .sup.e No Data                                                           

                  TABLE IV                                                        ______________________________________                                        Liquid Product   Gas Composition (%)                                          Volume (ml)                                                                            Weight (g)  H.sub.2 O                                                                            CO     CO.sub.2                                                                           CH.sub.4                              ______________________________________                                        .sup.a       31.8        67   33     0.1  0.1                                 .sup.a                                                                        37                                                                                         43.0        65   35     0.1  0.1                                 11                                                                                         31.6        67   33     0.1                                      20                                                                            20                                                                                         42.0        65   33                                              21                                                                            19                                                                                         40.7        63   36          0.1                                 20                                                                            9                                                                                          30.2        63   33                                              17                                                                            ______________________________________                                         .sup.a Not Determined                                                    

EXAMPLE XX

A 450 ml-capacity reactor with a glass liner was charged with a mixtureof dicobalt octacarbonyl (12.0 mmole Co, 2.052 g), triphenylsilane (24.0mmole; 6.250 g) in 1,3-dioxolane (200 mmole, 14.82 g), water (200 mmole,3.60 g) and 1,2,4-trichlorobenzene (15.0 g). The mixture was flushedwith nitrogen, the reactor sealed, flushed with synthesis gas (CO/H₂,1:2), pressured to 2000 psi with CO/H₂ (1:2) and heated to 180° C. withagitation. At temperature, the pressure was raised to 5000 psi withCO/H₂ (1:2) from a large surge tank. The pressure in the reactor waskept constant throughout the remainder of the run by incrementaladditions of CO/H₂ from the surge tank. After four hours, the reactor isallowed to cool, the gas pressure (3400 psig) noted, and the excess gassampled and vented.

45.8 g of a two-phase liquid product was recovered. There was no solidprecipitate at this stage.

Analysis of the less-dense liquid phase (18 ml) shows it to contain:

53.2 wt % ethylene glycol

7.5 wt % ethylene glycol monomethyl ether

0.5 wt % propylene glycol

8.9 wt % diethylene glycol

19.5 wt % water

2.3 wt % methanol

1.1 wt % ethanol

1.0 wt % 1,2,4-trichlorobenzene.

EXAMPLE XXI

Example XXI was conducted following the same procedure as Example XX.The only difference was that the promoter used was tetraethylenegermane.The reactor was charged with a mixture of dicobalt octacarbonyl (12.0mmole Co, 2.052 g), tetraethylgermane (6.0 mmole, 1.133 g), in1,3-dioxolane (200 mmole, 14.82 g) and 1,2,4-trichlorobenzene (15.0 g).

After reaction, 40.1 g of a two-phase liquid product was recovered.There was no solid precipitate at this stage.

Analysis of the less-dense liquid phase (20 ml) shows it to contain:

55.3 wt % ethylene glycol

6.2 wt % ethylene glycol monomethyl ether

0.5 wt % propylene glycol

5.9 wt % diethylene glycol

20.9 wt % water

2.6 wt % methanol

1.1 wt % ethanol

1.3 wt % 1,2,4-trichlorobenzene.

What is claimed is:
 1. A process for making ethylene glycol comprisingreacting synthesis gas, a mixture of carbon monoxide and hydrogen, plus1,3-dioxolane in the presence of a catalyst containing an effectiveamount of cobalt-containing compound and a silane-containing promoter,selected from the group consisting of triethylsilane, triphenylsilane,hydroxytriphenylsilane, diphenylsilane, tricyclohexylsilane andtetramethylsilane, in a solvent selected from the group consisting ofhalogen-containing aromatic solvents from the group consisting of1,2,4-trichlorobenzene, o-dichlorobenzene, bromobenzene,1,3,5-tribromobenzene, p-bromotoluene, chlorobenzene ando-dibromobenzene, and hydrocarbyl ether solvents, at a temperature of atleast 50° C., and a pressure of at least 500 psi.
 2. The process ofclaim 1, wherein the molar ratio of cobalt-to-silane promoter is in therange from 1:0.1 to 1:100.
 3. The process of claim 1, wherein thecobalt-containing compound is selected from the group consisting ofcobalt oxides, cobalt salts of a mineral acid, cobalt salts of acarboxylic acid and cobalt carbonyl or hydrocarbonyl derivatives.
 4. Theprocess of claim 3, wherein the cobalt-containing compound is from thegroup consisting of dicobalt octacarbonyl, cobalt(II) oxide, cobalt(II)nitrate, cobalt(II) acetate or cobalt acetylacetonate.
 5. The process ofclaim 4, wherein the cobalt-containing compound is dicobaltoctacarbonyl.
 6. The process of claim 1, wherein the silane promoter isselected from the group consisting of triethylsilane andtriphenylsilane.
 7. The process of claim 1, wherein the temperature isbetween 50° C. and 350° C.
 8. The process of claim 1, wherein thetemperature is between about 100° C. and 220° C.
 9. The process of ofclaim 1, wherein the pressure is between 1000 psi and 6000 psi.
 10. Theprocess of claim 1, wherein the desired synthesis of ethylene glycol isconducted in the presence of a halogen-containing aromatic solventselected from the group consisting of 1,2,4-trichlorobenzene,o-dichlorobenzene, bromobenzene, 1,3,5-tribromobenzene, p-bromotoluene,chlorobenzene and o-dibromobenzene.
 11. The process of claim 1, whereinthe desired synthesis of ethylene glycol is conducted in the presence ofa hydrocarbyl ether solvent selected from the group consisting ofp-dioxane and anisole.
 12. A process for making ethylene glycol fromsynthesis gas, i.e., a mixture of carbon monoxide and hydrogen, and1,3-dioxolane which comprises reacting said synthesis gas and1,3-dioxolane in a liquid phase containing an effective amount of cobaltcarbonyl compound and a silane containing promoter dispersed in a1,2,4-tricholorobenzene solvent at a temperature of from about 100° C.to 220° C. and a pressure of from about 1000 psi to 6000 psi.